Damage is estimated around $1 million but could increase, officials said.

Three boats caught fire and others were damaged as a result off Constitution Road in Charlestown late Tuesday night causing about $1 million in damage, according to the Boston Fire Department.

Two of the boats have sunk there were no injuries and there were no one on the boats at the time of the which came in around 11:20 tonight. The approximate damages at 1 million, FIU to investigate the cause companies remain for hot spots ⁦⁦@USCGNortheast⁩ pic.twitter.com/cw6JEXX4o2

Two of the charred boats ended up sinking, the department reported at 1:24 a.m.

Firefighters didn’t release an initial idea of what the cause was and are continuing to investigate, according to Brian Alkins, a department spokesman. He said the estimation of the damage will likely increase.

“There were a couple of boats that were exposed,” Alkins said, adding that they were all covered with plastic for the winter and some of that melted.

U.S. Coast Guard Northeast said its “pollution-response” team will be helping with cleanup on Wednesday.

Coast Guard pollution-response crewmembers are assisting with clean-up efforts near Constitution Marina today. Great job by our partner agencies for containing and putting out the fires last night! No injuries reported.@BostonFire#Boston#Firehttps://t.co/D5d5ChdKuC